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Gear / Technical Help => Remote Power => Topic started by: Chuck on September 07, 2011, 06:46:06 PM
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I need to charge a 12v SLA battery
Specifications:
Chemistry Lead Acid
Voltage 12.0 V
Capacity 5 Ah
Rating 60 Whr
Cell 6 cells
Is there any reason I can't just use a 12v DC wall-wart to charge it?
I know I shouldn't leave it charging more than say 24 hours...
I'm trying to get a 12v power source on the cheap.
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I think the charging voltage needs to be slightly higher than 12v. More like 13.5v, but I reserve the right to be an idiot.
I probably wouldn't recommend a charger that isn't intelligent. it should at minimum have overcharge protection.
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You cannot just use a 12v wallwart to charge an sla as the is nothing to stop the charging and nothing to tell you when the battery is charged.
You may want to try buying a setup at battery space as you can get unregulated liOn packs rated at 11.1v with charger for around $50
Ask in the ys for a 12v sla charger if $50 is too much
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the cool thing about SLA batteries is that they are all the same...not literally but as for chargers. I have a charger for car batteries that will do two low amperage setting and one high. Well actually I have a bubba bad charger that I used in my repair shop but we don't need something that puts out 60 amps.....back on topic. you can use the lower settings to charge a SAL battery and if it has a trickle setting it can stay connected and will keep it charged. DOWNSIDE...the charger will have two large alligator type clips and not be set up to a 4pin if it is something like the eco charges. but if you have just the bayonet slide on connectors you can clip it on and you're all set. Can be found pretty reasonable of you shop around
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I make my own wires and cables. I abandoned the 4 pin XLR's connectors for battery power a while ago. They are just too bulky and overkill for my needs.
I'll probably hit the local electronics surplus warehouse for a proper 12v charger then. Batteries Plus sells one that'll work for $21, but, as I said, I'm doing this on the cheap.
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There are several circuits available, here are a couple so you could build your own charger...
http://www.circuitstoday.com/lead-acid-battery-charger
(http://www.circuitstoday.com/wp-content/uploads/2008/03/battery-charger.jpg)
http://alectronics.blogspot.com/2010/09/12v-battery-charger-for-sealed-lead.html
(http://4.bp.blogspot.com/_oH9cuSJx7ZY/Ss7esgI9-VI/AAAAAAAAB6s/MsYTQrHgknc/s320/12V_Battery_Charger_SLA_Blocks.gif)
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Hmmm... that's a good idea!
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In the mid 90's I built the one on page 70 fig 13-2 from Encyclopedia of Electronic Circuits Vol 4. It made an awesome charger for SLA's. Attached here is a PDF of that circuit.
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http://www.ebay.com/sch/i.html?_from=R40&_trksid=p5197.m570.l1313&_nkw=battery+tender+12V+charger&_sacat=See-All-Categories
I used Battery Tender chargers back in the day and you can get the Jr version for about $20.
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In the mid 90's I built the one on page 70 fig 13-2 from Encyclopedia of Electronic Circuits Vol 4. It made an awesome charger for SLA's. Attached here is a PDF of that circuit.
Yeah, I probably have most of the parts already.
If I can't find a cheap one I may just build my own.
Though, I have started to value my time more lately. Putting hours into doing something like this the right way will take some time.
Thanks for the circuits!
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Man, I'm really rethinking the SLA thing again...
Even the relatively small 5 amp 12v SLA I have is so friggin' heavy.
There are tons of relatively cheap 12v Li-ion's (Hong Kong) on eBay, but I haven't read anything good about them here.
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QFT
Even the relatively small 5 amp 12v SLA I have is so friggin' heavy.
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I found what I needed today at Harbour Freight Tools for $9.99.
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Ahh, is this it?
http://www.harborfreight.com/automotive-motorcycle/battery/automatic-battery-float-charger-42292.html
I found what I needed today at Harbour Freight Tools for $9.99.
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Yeah, that's it. It was on sale for $9.99. I just got finished soldering some connectors on it.
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Just a thought, I used to fuse the output of SLA's back when I used to use them.
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Man, I'm really rethinking the SLA thing again...
Even the relatively small 5 amp 12v SLA I have is so friggin' heavy.
There are tons of relatively cheap 12v Li-ion's (Hong Kong) on eBay, but I haven't read anything good about them here.
I have one and cannot say there are any issues with the power it supplies. The draw backs are no metering and an easy to hit on/off switch. I have a buddy who has posted "noise" from them but it is below the self noise of mics....